The company FutureShip has created an enormous concept ferry that runs entirely using alternative energy — and it could be carrying passengers on short trips in just five years. Its designers boast that the ferry is a zero emissions vessel. But how can that be?

The surplus electricity generated by wind turbines in northern Germany and Denmark is to be used to produce hydrogen. This can be transformed back into electrical energy by the fuel cells on board the ship in order to supply the electrical pod drives. Any excess electricity is stored in batteries to cover peaks in demand. Modern hull lines, optimized propeller shapes and efficient procedures in port play a vital role in reducing the overall energy needs.

These ferries are also using less energy because they're designed for short trips of a day or two before it bunkers.

Diesel engines and gas turbines had to be ruled out, with a mix of photovoltaic systems, fuel cells and Flettner rotors crystallizing out as being the most suitable solution. The design process yielded a double-ended ferry with space for 1,500 passengers and 2,200 lane metres for vehicles. Located on deck, the hydrogen tanks can accommodate 140 cubic metres - enough for a passage of 48 hours. Deep down in the belly of the ship, where they do not take up space unnecessarily, the fuel cells offer a rated power of 8,300 kilowatts and the storage batteries a capacity of 2,400 kilowatt-hours. The nominal speed of the ferries is set at 17 knots - the parameter used for sizing the fuel cells. To accelerate up to 18 knots, the four three-megawatt pod drives draw additional current from the batteries.